1. Field of the Invention
The present invention relates to a light shading device for a camera having a focal plane shutter.
2. Description of the Prior Art
In the case of a camera having a conventional focal plane shutter in which both the leading and trailing shutter curtains having their ends wound on drums so as to run in front of the exposure window, it is well known that even when the shutter is closed, the light entering from the front surface of the camera comes through the exposure window, above and below the shutter curtain by reflection, to expose the film. In order to prevent such light from reaching the film, various kinds of light shading devices having an elastic light shading curtain, provided in the running path of the shutter curtain in such a manner that its end is normally in elastic contact with the shutter curtain, have been proposed. Such light shading devices have an excellent light shading effect because, even if the positions of the shutter curtains change before and after the shutter charge, namely in the state when the trailing shutter curtain covers the exposure window and in the state when the leading shutter curtain covers the exposure window, the end of the light shading member is in contact with the shutter curtain without fail.
For example, Japanese Utility Model Application Laid-Open No. Sho 51-115031 discloses a light shading device wherein the base portion of a piece of cloth, bent in advance, is fixed on the support provided near the shutter curtain so as to be parallel to the running direction of the shutter curtain in such a manner that the end of the cloth piece is in elastic contact with the shutter curtain. Further, as is disclosed in Japanese Utility Model Application Laid-Open No. Sho 50-65418, the mount surface of the support is inclined with respect to the shutter curtain, and the base portion of a flat cloth curtain is fixed in such a manner that its end is in elastic contact with the shutter curtain.
However, because the soft and elastic cloth curtain which has been bent by pressing, becomes straight with the lapse of time, the contact state with the shutter curtain changes so that the light shading efficiency decreases, while the shutter time is undesirably influenced because the friction with the shutter curtain changes.
Further, in the latter case, the treatment of the inclined mount surface is difficult and if the inclined mount surface is formed with another member in order to escape this difficulty, the construction becomes complicated and occupies much more space.